Many people are interested in fishing and camping. Generally, a fishing lover or a camping lover would carry a cooler box along with him or her for storing fish caught or food and/or beverage. Most of the currently available cooler boxes are manufactured by preparing an outer shell, an insulation layer and an inner shell. The insulation layer and the inner shell are sequentially positioned on an inner side of the outer shell, such that the insulation layer is located between the outer shell and the inner shell. Then, the outer shell, the insulation layer and the inner layer are sewn together using a tool or a machine.
In the process of sewing the outer shell, the insulation layer and the inner layer together, a handling worker has to simultaneously firmly grip on the outer shell, the insulation layer and the inner shell with two hands all the time, lest the outer shell, the insulation layer and the inner shell should become dislocated during the sewing process. In the event the outer shell, the insulation layer and the inner shell are dislocated, it is possibly they could not be firmly connected to one another and additional time is required to rework the cooler box and sew the outer shell, the insulation layer and the inner shell together again. In brief, in the past, the components of the cooler box are connected in a way that could not shorten the assembling time to thereby adversely affect the productivity of the cooler box.